Question

Please describe the key principle of the contiguous memory allocation method. What are the hardware support for contiguous memory allocation? What are the key disadvantages of the contiguous memory allocation method?

Answer 1

Contiguous Allocation:

In this method, each file or entity occupies a contiguous set of blocks on the main memory. All the available memory space remains in one place. It means freely available memory partitions are not scattered across the whole memory space. When any user process request for the memory a single section of the contiguous memory block is given to that process according to its need. We can achieve contiguous memory allocation by dividing memory into the fixed-sized partition.

Hardware support:

Hardware approach to manage memory is to load each process in contiguous space. The OS is allocated space first, and the the remaining available memory is allocated to processes as needed.

Disadvantages:

1. The disk will become fragmented.
2. This method suffers from both internal and external fragmentation. This makes it inefficient in terms of memory utilization.
3. It may be difficult to have a file grow.
4. Increasing file size is difficult because it depends on the availability of contiguous memory at a particular instance.